Zadanie 1a
Outline why compound A cannot be a hydrocarbon.
Chemistry HL Paper 2, May 2024, TZ2
Zadania wzorowane na pytaniach z tego arkusza: te same umiejętności, format i punktacja, inne dane i kontekst. Treści arkusza IB nie publikujemy.
Dodaj cały arkusz do zestawuZadanie 1b
Determine the empirical formula of A.
Zadanie 1c
At 150.0 °C and a pressure of 1.00 × 105 Pa, the vapour of A has a density of 2.45 × 103 g m−3. Determine the molar mass of A and hence its molecular formula. Use sections 1 and 2 of the data booklet.
Zadanie 1d
The infrared (IR) spectrum of A is given below. Identify the bond that gives rise to absorption B. Use section 20 of the data booklet.
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Zadanie 1e
When A is refluxed with excess acidified potassium dichromate(VI), K2Cr2O7, the product is compound E, whose molar mass is greater than that of A. From this information alone, identify one functional group in E.
Zadanie 1f
Deduce one possible structural formula of A that fits all of the evidence above.
Zadanie 2a
Give the full electron configuration of a nitrogen atom in its ground state and state how many of its electrons are unpaired.
Zadanie 2b
(i) Draw a Lewis (electron dot) structure of the nitrite ion. (ii) Deduce the formal charges of the nitrogen atom and of both oxygen atoms, and add them to the structure you drew in (i). (iii) Predict the shape of the ion and the size of the O-N-O bond angle.…
Zadanie 2c
Suggest a length, in pm, for the nitrogen-oxygen bonds in the nitrite ion and explain your choice. Use section 11 of the data booklet.
Zadanie 2d
Chlorine molecules, Cl2, and bromine molecules, Br2, can both be split into atoms by radiation. Use section 12 of the data booklet. Explain how the wavelengths of radiation that can split Cl2 and Br2 molecules into atoms compare.
Zadanie 2e
Atmospheric carbon dioxide and the pH of surface seawater were measured at a monitoring station over nineteen years. The graph shows the annual mean values. (i) Outline the relationship between the carbon dioxide mixing ratio and the pH of the seawater. (ii)…
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Zadanie 3a
(i) State one environmental problem caused by acid rain. (ii) Write an equation for the reaction of sulfur trioxide, SO3, with water in the atmosphere, in which an acid forms.
Zadanie 3b
Potassium oxide, 0.0150 mol, was dissolved in water and the solution was made up to a final volume of 250.0 cm3. (i) Write a balanced equation for the reaction of potassium oxide with water. (ii) Calculate the pH of the solution.
Zadanie 3c
Hypochlorous acid, HOCl(aq), has Ka = 2.95 × 10−8. (i) Determine the pH of an aqueous solution of hypochlorous acid of concentration 0.150 mol dm−3. (ii) State one assumption you made in the calculation in (i). (iii) State…
Zadanie 4a
Write the equilibrium constant expression, Kc, for this reaction.
Zadanie 4b
At 298 K, Kc has the numerical value 1.50 × 10−3. Calculate the value of the ratio in a solution in which [Cl−] is 6.00 mol dm−3.
Zadanie 4c
Explain the colour of Co2+(aq) in terms of its electronic structure, using section 15 of the data booklet.
Zadanie 4d
State, with a reason, how the value of Kc changes when the temperature is raised, given that ΔH⊖ > 0.
Zadanie 4e
State, with a reason, how the position of this equilibrium is affected when aqueous silver nitrate, AgNO3(aq), is added. Ag+(aq) + Cl−(aq) → AgCl(s)
Zadanie 5a
Suggest how the parts of the IUPAC name prop-2-enal match the structure of the compound.
Zadanie 5b
Butane, C4H10, and propenal have similar molar masses, yet propenal is the less volatile. Compare and contrast the intermolecular forces in the two substances to account for this difference.
Zadanie 5c
Propenal can be made by the dehydration of propane-1,2,3-triol (glycerol). CH2(OH)CH(OH)CH2OH(l) → CH2=CHCHO(g) + 2 H2O(g) (i) Calculate the standard enthalpy change of this reaction, using ΔHf⊖ of propenal(g)…
Zadanie 5d
Propenal can be oxidised to compound G. G produces bubbles of gas when it is added to aqueous sodium hydrogencarbonate. The mass spectrum of G is shown. Deduce what G is and give two reasons, based on the mass spectrum.
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Zadanie 5e
20.0 cm3 of propane is mixed with 150.0 cm3 of oxygen and burnt completely. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l) Determine the total volume of gas present once the products have cooled to the starting temperature and…
Zadanie 5f
State one reason why real gases such as butane and ammonia deviate more from ideal behaviour as the pressure increases.
Zadanie 5g
Oxidation of cyclohexanol, C6H11OH, gives cyclohexanone. Cyclohexanol itself is made by adding water to a compound H. Draw the structure of H.
Zadanie 5h
1-Bromopropane reacts with aqueous sodium hydroxide to give propan-1-ol. (i) Identify the type of mechanism for this reaction. (ii) Explain the mechanism, using curly arrows to show the movement of electron pairs.
Zadanie 5i
2-Chloropentane exists as two stereoisomers. (i) Using wedge-dash notation, draw the two stereoisomers of 2-chloropentane. (ii) Outline a way of telling the two enantiomers apart.
Zadanie 6a
The student then followed the reaction with a spectrophotometer, which records the light absorbed by the mixture and so gives the concentration of the dye throughout the reaction. The graph shows [D+] against time for experiment 3. (i) Use the graph to…
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Zadanie 6b
Explain, in terms of collision theory, why raising the temperature of the reaction mixture from 20 °C to 30 °C increases the rate of the reaction between D+ and OH−.
Zadanie 7b
Potassium iodide, KI, and potassium metal, K, are both solids at room temperature. State the type of bonding in each of the two solids and describe it.
Zadanie 7c
Molten potassium iodide is electrolysed. Write the half-equation for the reaction at each electrode: the positive electrode (anode) and the negative electrode (cathode).
Zadanie 7d
An aqueous solution of potassium iodide is electrolysed. Determine the product at each electrode, using section 19 of the data booklet.
Zadanie 7e
The diagram shows a voltaic cell made from a zinc half-cell and a copper half-cell. The salt bridge contains aqueous potassium nitrate, KNO3(aq). Electrons flow through the external circuit in the direction shown. Use section 19 of the data booklet to…
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Zadanie 7f
Use the data below, together with sections 9 and 12 of the data booklet, to determine the lattice enthalpy of potassium iodide. K(s) → K(g) ΔH = +89 kJ mol−1 I2(s) → I2(g)…
Zadanie 7h
Predict what happens, and give a reason, when bromine water is added to aqueous potassium chloride and, in a separate experiment, to aqueous potassium iodide.